Is a Portable CO2 Fire Extinguisher Safe for Indoor Use?

Working Principle and Indoor Suitability of Portable CO2 Fire Extinguisher

Portable CO2 Fire Extinguisher is a critical device for fighting initial-stage indoor fires. Its core extinguishing mechanism combines physical dilution with localized cooling:

Smothering: When carbon dioxide is released from the high-pressure cylinder, it expands rapidly and displaces the oxygen surrounding the fire. When the oxygen concentration in the environment drops below 12%-14%, the combustion chain reaction cannot be sustained.
Cooling: CO2 forms small "dry ice" crystals upon discharge, which absorb ambient heat and assist in lowering the temperature of the fire source.
Indoor Advantages:
- No Pollution or Residue: As a "clean agent," it does not leave sticky dust or corrosive powder like dry powder extinguishers, making it the first choice for server rooms, laboratories, and libraries.
- Electrical Insulation: Carbon dioxide is non-conductive and can safely extinguish fires in live electrical equipment.

Core Technical Parameter Comparison Table

Performance Index	2kg Model (Common Office Use)	5kg Model (Common Industrial/Server Room Use)
Fire Rating	34B	55B / 70B
Filling Pressure (20°C)	5.5 - 6.0 MPa	5.5 - 6.0 MPa
Jet Range	1.5 - 2.5 meters	2.5 - 4.0 meters
Continuous Discharge Time	≥ 8 seconds	≥ 12 seconds
Operating Temperature Range	-10°C to +55°C	-10°C to +55°C
Cylinder Material	High-quality Carbon Steel / Aluminum Alloy	High-quality Carbon Steel / Aluminum Alloy
Min. Indoor Area Requirement*	Approx. 11 square meters or more	Approx. 27.5 square meters or more

*Note: According to safety standards, it is recommended to have at least 5.5 square meters of free floor space for every 1kg of CO2 to prevent the risk of suffocation due to low oxygen concentration.

Safety Boundaries for Indoor Use

When operating a Portable CO2 Fire Extinguisher indoors, the following physical parameter limits must be strictly observed:

Safety Distance: The operator should stand upwind of the fire, starting the discharge at a distance of approximately 2-3 meters from the fire source.

Low Temperature Protection: The temperature at the nozzle outlet can be as low as -78°C. During operation, you must hold the specially designed insulated handle. Strictly forbid touching the horn or discharge tube, as this can cause severe frostbite.

Space Constraints: After use in confined small rooms (such as elevators or storage rooms), personnel must evacuate immediately and turn on ventilation systems.

Key Steps for Using Portable CO2 Fire Extinguisher Indoors

In indoor environments, the correct operating sequence and safety distance are vital for both extinguishing efficiency and operator safety.

PASS Standard Operating Method

Follow the internationally recognized PASS steps, optimized for the physical characteristics of CO2 extinguishers:

Pull: Pull out the safety pin. This usually breaks the lead seal or plastic tie.

Aim: Aim the horn nozzle at the base of the fire. Must hold the insulated handle at the base of the nozzle.

Squeeze: Squeeze the lever to release the agent as a high-pressure gas mist.

Sweep: Sweep from side to side at the base of the fire, moving from near to far until the flames are completely extinguished.

Indoor Operation Parameter Comparison

Operating Dimension	Live Electrical Fire	Flammable Liquid Fire (Class B)
Initial Safety Distance	≥ 1.5 meters	2.0 - 3.0 meters
Aiming Point	Directly at the burning parts	Base of fire, sweeping edge to center
Power Handling	Must cut power first if possible	Watch for the direction of flowing fire
Coverage Method	Concentrated discharge on components	Rapid side-to-side sweep for gas layer

Special Warnings for Indoor Use

Asphyxiation Risk: After using a Portable CO2 Fire Extinguisher in an enclosed room with a volume of less than 30 cubic meters, the operator must evacuate immediately.

Prevent Re-ignition: CO2 extinguishers primarily rely on smothering and have limited cooling effects. Observe for at least 15 minutes to ensure objects have cooled down.

Noise Preparation: Discharge indoors produces a loud noise. Operators should remain calm.

Indoor Safety Storage and Maintenance Requirements

Indoor Storage Environment Requirements

Temperature Control: Must be stored between -10°C and +55°C. Keep away from radiators or direct sunlight.

Physical Location: Hang in a dry area. The bottom should be no less than 0.08 meters from the ground, and the top no more than 1.5 meters.

Stability: Use dedicated brackets to prevent the cylinder from being knocked over.

Maintenance and Inspection Parameter Table

Maintenance Item	Monthly Inspection	Annual Professional Test
Detection Method	Visual and manual check	Weighing Method
Agent Standard	Seal intact, pin in place	Leakage ≥ 10% requires refill
Cylinder Safety	Check for blockages	Pressure test every 5 years
Scrap Age	Check date	12 years from manufacture

Indoor Maintenance Checklist

Weight Logic: Subtract the tare weight from the measured weight. If the result is lower than 90% of the rated agent weight, it must be refilled.

Horn Inspection: Check the horn nozzle for dust blockages regularly.

Seal and Pin: Ensure the safety pin is locked and the seal is intact.

Frequently Asked Questions (FAQ)

Q: Why does the Portable CO2 Fire Extinguisher have no pressure gauge?

A: CO2 exists as a liquid in the bottle. Its saturated vapor pressure changes with temperature rather than amount. The only reliable standard is weighing.

Q: How effective is it for Class A fires (wood, paper) indoors?

A: Limited. It only puts out surface flames. There is a high risk of re-ignition.

Q: How does CO2 concentration affect the human body indoors?

CO2 Concentration	Physiological Reaction	Safety Suggestion
0.04%	Normal atmosphere	Safe
2% - 3%	Deeper breathing	Suggested to leave area
5%	Difficulty breathing	Must evacuate
Above 10%	Unconsciousness or death	Strictly forbidden to stay